如何比较 c# 中逻辑上相等但技术上不相等的字节数组（ byte[] ）？

Question

I have two large byte-arrays (byte[]) that I want need to compare. They should by logically equal but are not always technically equal. The reason being differences in how floating point numbers are represented in these two arrays.

Is there a way of comparing these by idenfitying the floating point numbers and testing if the numbers are within a error tolerance?

I suspect this situation is caused by the fact that one of these byte-arrays has been stored and retreived from a database (postgres).

So far I compare the two byte arrays like so:

public static bool AreEqual(byte[] a, byte[] b)
{
    if (a.Length == b.Length)
    {
        for (var i = 0; i < a.Length; ++i)
        {
            if (a[i] != b[i])
            {
                return false;
            }
        }
    }

    return true;
}

(Initially I serialized to JSON, but I had the same problem with that. Thought serializing to bytes would fix this, but no).

Answer 1

First you need to convert your byte arrays to float arrays, if that is what they represent. You can either use a binary reader , or you could convert your array to a span, cast it , and copy the result to a new array.

For comparison Linq has a SequenceEquals method that compares all the individual values, and allows for a equality comparer to specify how that comparison is made.

You need to implement this equality comparer yourself, after reading about how floating point numbers should be compared. See Floating point guide and how to compare floating point numbers